A Republican super PAC on Friday will launch a sharp television assault on embattled Massachusetts Rep. John Tierney (D).

The ad from the YG Action Fund asks what "the truth" is about the eight-term Congressman and tells viewers about the gambling ring of Tierney's wife's family.

"What's the truth about John Tierney?" a female narrator asks, backed by ominous music. "This much we know: His family ran an illegal gambling operation for years. His wife, Patrice, went to jail as Tierney sat silent in court. His own brother-in-law says Tierney knew everything and is a liar."

"He threw my sister under the bus to save his political career," a gravely male voice says in the ad.

The female narrator comes back in to end the ad: "Imagine what we don't know. It's time for John Tierney to man up and tell the truth — the whole truth."

Robert Eremian, one of Tierney's brothers-in-law, in June told the Boston Globe something almost identical to the quote from the male voice in the ad. "He threw my sister under the bus for his political career," Eremian said, according to the Globe.

Tierney faces a tough race with former state Sen. Richard Tisei (R). Tierney has not been accused of any wrongdoing.

The Tierney campaign sent a statement from the Congressman to Roll Call.

"What a coward Richard Tisei is," Tierney said. "Hiding behind his shadowy right wing allies as they attack my wife and my relationship with her, all in order to win a political campaign that he can't win on the issues.

"It's as low as it gets," Tierney said.

Tierney campaign manager Matt Robison also knocked the ad.

"This disgusting attack on Patrice Tierney's painful family crisis shows that Paul Ryan's right-wing Republican group will say and do anything to elect their hand-picked Republican candidate, Richard Tisei, because he supports their disastrous plans to cut taxes on the wealthy and pay for it by ending Medicare," Robison said.

The YG Action Fund is a super PAC formed by former aides to House Majority Leader Eric Cantor (R-Va.). Ryan, the Wisconsin Congressman and Republican vice presidential nominee, does not appear to have any connection to the group.

"It is disgusting," said Brad Daysrping, senior adviser to the super PAC. "But, unfortunately for the people of the sixth district of Massachusetts, everything in that ad is accurate."

The pointed ad is backed by $894,000 over two weeks on Boston broadcast television, though the buy could be extended and other ads could be cycled into the buy.